1. Introduction

Objective:

  • Make statistical analysis and visualization for the volumetric evolution of ISSRs in CONUS in 2020.
  • Aims to explore the RAP Analysis data and find out potential patterns about ISSRs, involving the following aspects:
    • Statistic analysis for the entire 3D grid
      • Volumetric evolution of ISSR by hour/day/month
      • Volume of ISSRs at different hours in a day
      • Ceilings and floors by hour/day/month
    • Statistic analysis for horizontal grids
      • Volume of ISSRs at different pressure levels
    • Statistic analysis for vertical grids
      • Volume of ISSRs at different latitude
      • Volume of ISSRs at different longitude

Backgrond

  1. Contrail-Cirrus Clouds are estimated to contribute 2% of the Earth‘s total anthropogenic global warming.
  2. Contrail-Cirrus Clouds are formed from the emissions of jet engines under certain atmospheric conditions, like humidity and cold.
  3. These atmospheric conditions are known as Ice Super Saturated Regions (ISSR).
  4. ISSRs are identified as regions with a relative humidity with respect to ice above 100% and a temperature below 233K (to avoid regions of supercooled water clouds).
  5. Studying the volumetric evolution of ISSRs can help to facilitate the design of the air transportation system, thereby helping to prevent climate warming. To be specific, airlines can produce fewer contrail-cirrus clouds by cruising at the time when the volume of ISSRs is low or avoiding crossing ISS regions.

Datasets

  1. Dataset Description: Rapid Refresh (RAP) Analysis Data with lambert conformal projection of a 20-km resolution. To reduce the cells for analysis, 4 adjacent 20km*20km cells are combined to make a 40-km resolution grid.
  2. Dataset Owner: the U.S. National Oceanic and Atmospheric Administration (NOAA)
  3. Dataset Type: open source
  4. Dataset Size: 50GB (hourly updated data in 229 days, all available archive data in 2020)
  5. Dataset Time Range: From 5/17/2020 to 12/31/2020
  6. Dataset Area Range: The contiguous United States (CONUS)
  7. Dataset Access: HTTPS server

2. Statistic analysis for the entire 3D grid

2.1. Volumetric evolution of ISSR by hour/day/month

  • The volume of the ISSR tends to be higher in the late Fall and the early Winter season.
  • Specifically, the monthly average volume of ISSR in December is two times higher than in August.

2.2. Volume of ISSRs at different hours in a day

  • The monthly average volume of ISSR tends to be the highest in the afternoon.
  • In December, the monthly average volume of ISSR at midday is 51 percent higher than that at midnight.

2.3. Ceilings and floors by hour/day/month

  • The two-line graphs are ceiling and floors at each DateTime and AVG ceiling and floors by month.
  • Through the overall trend and the trend of each month, we could find the concentration of ceiling and floor from 15000 to 50000.
  • According to the monthly AVG volume of ISSR is the lowest point in August, there is an upward trend as the winter enters.
  • So when mapped to the monthly AVG ceilings and floors, the distance between the two lines in August is the closest.
  • After the winter, the distance between the two gap is getting bigger and bigger.

3. Statistic analysis for horizontal grids

3.1. Volume of ISSRs at different pressure levels

  • As we could find that before 27500Pa, the volume of ISSR shows an overall growth trend, but when the pressure level is higher than 27500Pa. The volume of ISSR shows a dramatic downward trend.
  • When we add each month to the pressure level, with 25,000PA as the dividing point, the Volume of ISSR is mainly formed in summer in high altitude areas, and formed in winter in low altitude areas.

4. Statistic analysis for vertical grids

4.1. Volume of ISSRs at different latitude

The following picture is the visualization of the latitude summary table. It consists the data of the average volume of the ISSR in whole one year based on each latitude ID. The latitude ID ranges from 1 to 120. Specifically, the latitude ID represents the area which starts from the south to the North area. The smaller the latitude ID value, the closer the area to the South area. Vice versa, the higher ta value of the latitude ID, the closer it is to the North area.

The latitude ID is sorted from 1 to 120 which shows the latitude area from the south to the north area. Through the following picture, it can be seen that there is a trend between the average volume of the ISSR and the Latitude.It shows that the closer the area to the north, the higher the average volume of the ISSR according to the whole one year data.

The plot below shows the visualization of the the monthly average volume of the ISSR of each latitude. It contains the months, latitude ID, and the average volume of the ISSR. Specifically, it shows the average volume of the ISSR of each latitude ID from month 5, which is May, to month 12, which is December. The year period of these months is 2020.

In every month, we can see there is an increment trend of the average volume of the ISSR when it gets closer to the North area. It brings a conclusion that the closer to North area, the higher the average volume of the ISSR in every month.

4.2. Volume of ISSRs at different longitude

The following picture is the visualization of the summary table of the average volume of the ISSR of each longitude for one year. The table contains the longitude ID and the average volume of the ISSR. The longitude ID ranges from 1 to 150 which represents the higher the value of the longitude ID, the closer the area to the East. Again, it shows the trend of the average volume of the ISSR from the West to the East area in one year. According to the following picture, it shows there is a decrement of the average ISSR volume in the middle area between the East and the West area.

The picture blow is the visualization of the average ISSR volume in every month as summarized in the previous table. Specifically, it shows the summary of the average ISSR volume over the months based on each longitude ID. The month ranges from month 5, which is May, to month 12, which is December. The year period of these months is 2020.

According to the plot above, the trend from the whole months is hard to conclude as the average ISSR volumes is fluctuating in every month. However, there are tendencies that the average volume is getting lower in the middle, which is between West and East area, from October to November 2020.